期刊
JOURNAL OF ENERGY CHEMISTRY
卷 80, 期 -, 页码 392-401出版社
ELSEVIER
DOI: 10.1016/j.jechem.2023.01.010
关键词
Nickel sulfide anodes; Reaction reversibility; Structure rebuilding; In -situ TEM; Lithium-ion battery
The fundamental reaction behaviors of nickel sulfide (NixSy) as lithium-ion battery anodes were investigated using in-situ TEM. Ni3S2 was found to be the electrochemically stable phase. During lithiation, NixSy nanoparticles evolved into a mixture of Ni nanocrystals embedded in Li2S matrix, forming a porous structure. In delithiation, the Ni3S2 phase recrystallized to form a compact and interconnected network. Carbon substrate improved the tolerance for size-dependent pulverization of NixSy nanoparticles. This work enhances the understanding of electrochemical reaction behavior and aids in the rational design of high-energy density battery anodes.
The electrochemical performance of lithium-ion batteries, i.e. specific capacity and cyclability, is primar-ily determined by chemical reversibility and structural stability of the electrodes in cycling. Here we have investigated the fundamental reaction behaviors of nickel sulfide (NixSy) as lithium-ion battery anodes by in-situ TEM. We find that Ni3S2 is the electrochemically stable phase, which appears in the first cycle of the NixSy anode. From the second cycle, conversion between Ni3S2 and Li2S/Ni is the dominant electro-chemical reaction. In lithiation, the NixSy nanoparticles evolve into a mixture of Ni nanocrystals embed-ded in Li2S matrix, which form a porous structure upon full lithiation, and with the recrystallization of the Ni3S2 phase in delithiation, a compact and interconnected network is built. Structural stability in cycles is susceptible to particle size and substrate restraint. Carbon substrate can certainly improve the tolerance for size-dependent pulverization of NixSy nanoparticles. When NixSy nanoparticle exceeds the critical size value, the morphology of the particle is no longer well maintained even under the constraints of the car -bon substrate. This work deepens the understanding of electrochemical reaction behavior of conversion-type materials and helps to rational design of high-energy density battery anodes.(c) 2023 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences Published by Elsevier B.V. All rights reserved.
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